Deterioration of cold-stored tissue specimens due to lipid peroxidation: modulation by antioxidants at high subzero...

It is often necessary to store tissue specimens in subzero conditions for assay in batches. During storage at -20 degrees C we found that sufficient lipid peroxidation occurred in rat liver homogenates in phosphate-buffered saline to affect subsequent malondialdehyde assays. This peroxidation did not occur at -196 degrees C. The ratio of oxidized to reduced glutathione increased with storage at -20 degrees C and the level of conjugated dienes increased progressively. The addition of a specific free radical scavenger, superoxide dismutase (200 u/ml) reduced the level of malondialdehyde (P < 0.001) during -20 degrees C storage for periods of 28 days but failed to prevent the changes in the glutathione ratio or dienes. Storage in a less specific free radical scavenger, 0.25 molar sucrose/EDTA, instead of phosphate-buffered saline totally prevented the malondialdehyde production over similar storage periods.